City of Bainbridge Island approves herbicide use to fight noxious weeds

In a highly wooded region like western Washington, it’s to be expected that amidst the native vegetation there are also poisonous, invasive plants that present a health risk to both humans and animals if left unmonitored.

In a highly wooded region like western Washington, it’s to be expected that amidst the native vegetation there are also poisonous, invasive plants that present a health risk to both humans and animals if left unmonitored.

Bainbridge Island is no exception.

In fact, according to representatives with the Kitsap County Noxious Weed Control Board, the plant growth has become uncontrollable by hand or mechanical removal on the city’s public lands.

That’s why in a unanimous vote Monday, the city council approved a city partnership with the weed control board to begin using herbicides on toxic overgrowth along roadsides, public land and city-owned property.

“If we let this continue on the trajectory that it is right now, this will be the only thing on our roadsides,” said Danna Coggon of the noxious weed board.

Coggon advised that it’s the city and county’s responsibility to take care of its properties before noxious weeds begin to infest neighboring land.

“If you have folks on the island who actually have goats, sheep, cattle, horses, we’re actually endangering their animals because we’re not doing the responsible thing by taking care of our own properties,” Coggon said.

A 2003 city ordinance limits the use of herbicides on public land.

However, the council is authorized to allow the use of chemicals when it’s determined an emergency situation exists.

Coggon told the council Monday that the county doesn’t have the resources to manually keep up with weeds like tansy ragwort, which if ingested by an animal can cause cirrhosis of the liver.

“One of the things that many of you have probably noticed, is that there’s quite a bit of this along the roadsides,” Coggon said.

“It looks like a pretty flower, but honestly it’s probably one of the most insidious plants that we have in Kitsap County.”

According to Coggon, Bainbridge has become a playground for noxious weeds and they pose a threat to public health and the environment.

Pulling the weeds by hand, clipping the flowers and mowing alongside roads, she said, is not going to keep up with the growth.

The control board has identified class A noxious weeds on Bainbridge such as hogweed and class B weeds such as knotweed, hemlock, loosestrife and yellow archangel.

“These plants are a cancer on our lands,” Coggon said.

“Sometimes you have to use a little bit of chemotherapy to get rid of the cancer. You don’t want to use it all the time and everywhere, but sometimes you need a little bit and you need a targeted approach to actually manage the problem.”

With the council’s recent approval, the weed control board will team up with city staff and volunteers to visit individual sites.

The crew will pull as many plants as possible to limit the use of herbicides and cut and bag the flower heads.

Then county-licensed applicators will use backpack sprayers or direct injection to insert herbicide down into the root system of the plants.

In an area where there are mature plants, Coggon said, there are typically also thousands and thousands of rosettes — leafy, un-flowered clusters of the weed.

“To pull these we just don’t have the resources,” Coggon explained.

“The herbicide is taken down into the root system of these plants, whereas if we just pull it, a lot of these roots will break off in the ground and stay.”

To systemically treat the overgrowth, the weed-control effort will follow the same process used in 2007 when it worked on Bainbridge to beat back knotweed — a plant that grows 7 to 10 feet tall and has a root system that can spread 30 feet away from the parent plant in one season.

Crews will post signs 48 hours in advance at the site it plans to treat, apply the herbicide and stay on-site to answer questions from the public until the area is dry.

The team will return 24 hours later to pull the signs.

The control board will have crews return to the site several times throughout the year to pull any plants that are left behind.

Coggon said that every application will follow the best management practices approved by the Washington State Noxious Weed Control Board and the Nature Conservancy.